This thesis aims to explore and understand the structural and electrical properties of the antiperovskite Sr3SnO and the perovskite BaSnO3. Despite both being stannates, their properties are very different. Highly Sr-deficient Sr3-xSnO has been proposed as a possible topological superconductor because of its band structure is theoretically predicted to be topologically non-trivial, and a superconducting transition in bulk Sr3-xSnO (x ~ 0.5) polycrystalline ceramics is experimentally observed at ~ 4 K. In contrast, BaSnO3 is not topological, but it is a candidate as a next-generation transparent conducting oxide and wide band-gap semiconductor for power electronics. Bulk BaSnO3 crystals are reported to have room temperature mobilities above 300 cm2V-1s-1. The challenges in the research of Sr3SnO and BaSnO3 are also different. To date, the superconductivity in Sr3SnO has only been observed in highly Sr-deficient bulk polycrystalline ceramics containing secondary phases. The impurity phases make the study of the intrinsic properties of Sr3SnO difficult. Most importantly, the roles of these phases in the origin of superconductivity are poorly understood. Molecular beam epitaxy (MBE) of Sr3SnO films has been reported, but phase purity is not assured. As for BaSnO3, high-quality thin films are desired because they can be epitaxially integrated with various other perovskites to make advanced devices. Different MBE methods to grow BaSnO3 thin films have been developed. Still, the highest room-temperature carrier mobility values in films are between 150 to 180 cm2V-1s-1, well below the value observed in bulk crystals. Prior to the work discussed in this thesis, the upper limit of the carrier mobility inside BaSnO3 films was mainly attributed to threading dislocations. In this work, oxide MBE is demonstrated to be capable of growing phase-pure Sr3SnO thin films. Exploration within the phase-pure growth window achieved a film with a hole mobility of 400 cm2V-1s-1 (highest in literature) and carrier density of 3.7 × 1018 cm-3 (lowest in literature) at 10 K. However, none of the phase-pure films were superconductive, raising questions as to whether the hole carrier density was high enough given that the superconductive bulk Sr3-xSnO polycrystalline ceramics have carrier densities above 1021 cm-3. This motivated research using indium as a dopant to increase the hole carrier density. It was found that the hole carrier density could be precisely tuned by varying the indium source temperature. Unfortunately, even a film with a hole carrier density above 1021 cm-3 was still not superconductive. Therefore, the superconductivity observed in bulk Sr3-xSnO polycrystalline ceramics is possibly extrinsic. The same oxide MBE system was used to grow BaSnO3 thin films. Lattice-matched substrates were used to reduce the threading dislocations inside the BaSnO3 films. However, this reduction did not improve carrier mobility, indicating that other defects may play important roles. Therefore, point defects were investigated as the potential mobility limiting defect. Carbon concentrations in BaSnO3 films were measured using secondary ion mass spectroscopy. The result showed a mid-to-low 1018 atoms/cm3 carbon density. The origin of the carbon was found to be the SnO2 source material and associated with surface adsorbents. In addition, an analysis of the growth rate, x-ray diffraction patterns, and lattice constant indicates that Sn-rich and O-poor growth conditions were present during all the growths. The excess Sn ions were accommodated into the Ba sites to form SnBa antisite defects. Both point defects may pose an upper limit to thin film mobility.